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	<title>Document</title>
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	<script type="text/javascript">
	  //var a=prompt("哈哈请输入点什么东西吧");
	  //console.log(a);
	 // prompt就是专门弹出能够让用户输入的对话框
	  
	  var year=prompt("请输入你的出生年份");
	  var age=2018-year;
	  -alert("哈哈，你今年"+age+"岁了，我聪明吧");
	  
	  //声明了2个变量,
	</script>
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